How to Calculate Conversion Rate in GA4: How to Set Up & Measure Success

If you've recently migrated to Google Analytics 4 (GA4) or are diving deeper into its capabilities, you might have hit a familiar roadblock: where are the conversion rates? Specifically, where are the good old Session Conversion Rate and User Conversion Rate metrics we relied on in Universal Analytics (UA)?

You're not alone in this search. The truth is, GA4 handles conversions—and consequently, conversion rates—differently. It’s built on a flexible, event-based model, which is powerful but means some metrics we took for granted now require manual calculation.

Don't worry, it's not impossible! In this detailed guide, we'll dissect how conversions work in GA4, show you where to find the basic conversion data that is available, and most importantly, walk you through step-by-step methods to calculate essential conversion rates: Session Conversion Rate, User Conversion Rate, Landing Page Conversion Rate, and even specific eCommerce rates like Add to Cart Rate.

This post is for you if you're a web analyst, marketer, or any GA4 user feeling slightly lost without those familiar rate metrics. Let's dive in and bring clarity to your GA4 conversion analysis.

Conversions in GA4

First things first: let's clarify what a "conversion" means in the GA4 universe. Unlike Universal Analytics with its predefined Goal types (Destination, Duration, Pages/Session, Event), GA4 simplifies this significantly.

A conversion in GA4 is simply any event that you decide is important for your business and subsequently mark as a conversion. That's it. Generated a lead? Track a generate_lead event and mark it. Made a sale? The purchase event is your conversion. Submitted a contact form? Track contact_form_submitted and flag it.

How to Mark an Event as a Conversion:

1. Navigate to Admin (the gear icon ⚙️ in the bottom left).

2. In the Property column, click on Data display > Conversions.

3. You'll see a table of events already marked as conversions (by default, purchase is usually there for retail properties).

4. Click the blue "New conversion event" button.

5. In the "New event name" field, enter the exact name of an event you are already collecting data for (e.g., form_submission). GA4 will not let you mark an event that hasn't been received yet.

6. Click Save.

Your event will now appear in the Conversion events table and GA4 will start treating it as a conversion moving forward (data is not processed retroactively for this setting).

Keep in mind there's a limit: 30 custom conversion events for standard GA4 properties and 50 for GA4 360 properties. Choose wisely!

The key takeaway here is the shift in philosophy: GA4 offers immense flexibility by letting any tracked event become a conversion. The trade-off? It doesn't automatically compute session or user-based rates for every single one of these potential conversions like UA did for its Goals.

Finding Basic Conversion Data in GA4 Reports

Okay, so we've marked our important events as conversions. Where can we actually see the counts? GA4 provides several standard reports where conversion data appears:

• Reports Snapshot: Often includes a card summarizing total Conversions and potentially Conversion value. A very high-level glance.

• Traffic Acquisition Report: (Reports > Acquisition > Traffic acquisition). This is crucial. It shows Sessions, Users, Engaged sessions, and Conversions attributed to different traffic sources (Session default channel group, Session source / medium, etc.). This helps you understand which channels are driving conversions.

• Pages and Screens Report: (Reports > Engagement > Pages and screens). This report shows metrics like Views, Users, and Event count per page. You can add Conversions as a metric here. Use with caution: Seeing conversions alongside a page doesn't mean the page caused the conversion directly, just that a conversion happened later in the same session or by the same user who viewed that page.

• Events Report: (Reports > Engagement > Events). This lists all tracked events. Events marked as conversions will have a toggle under the "Mark as conversion" column enabled. It shows the total Event count and Total users for each event, including those marked as conversions.

• Conversions Report: (Reports > Engagement > Conversions). This report specifically lists only the events you've marked as conversions, showing their total Conversions count and associated Conversion Value (if configured).

The Built-in Rate (Singular-ish): eCommerce

There's an exception to the "no built-in rates" rule, primarily for eCommerce. If you have correctly implemented GA4's standard eCommerce tracking (events like view_item, add_to_cart, begin_checkout, purchase), GA4 does provide some useful rates, particularly in the Monetization reports:

• Purchase-to-view rate: Measures the rate at which users purchase items after viewing them.

• Cart-to-view rate: Measures the rate at which users add items to their cart after viewing them.

• eCommerce conversion rate: This is typically defined as (Sessions with a purchase event / Total Sessions) * 100%. You'll often find this metric (sometimes named Session conversion rate within this specific context) in the eCommerce purchases report.

The Gap: Notice what's missing? A universal, readily available Session Conversion Rate or User Conversion Rate that applies automatically to any conversion event you define (like a generate_lead or form_submission). That's the gap we need to fill.

The Missing Metrics: Why No Default Session/User Conversion Rate?

Why did Google omit these seemingly fundamental metrics from the standard GA4 interface? It boils down to GA4's core architecture:

1. Event-Based Model: GA4 is designed to track granular user interactions (events) across multiple platforms (web + app) and potentially long user journeys that span multiple sessions. The focus shifted from session containers to the user and their actions.

2. Flexibility Over Prescription: GA4 provides the building blocks: Events, Conversions (which are just flagged events), Sessions, Users. It leaves the calculation of specific ratios between these components largely up to the analyst. This allows for more custom analysis but requires extra setup for common KPIs.

Therefore, to get those classic conversion rates for non-eCommerce actions, or even custom-defined eCommerce success rates, we need to roll up our sleeves and calculate them ourselves. The primary tools for this within the Google ecosystem are GA4 Explorations and Looker Studio (formerly Google Data Studio). For more complex scenarios, BigQuery is the ultimate solution.

Calculating Session Conversion Rate in GA4

This is arguably the most sought-after "missing" metric. It answers: "What percentage of sessions on my site resulted in a conversion?"

Definition: (Total Conversions / Total Sessions) * 100%

Method 1: Looker Studio (Recommended)

Looker Studio is fantastic for this because you create the metric once, and it's available across your entire report.

1. Connect GA4: Add your GA4 property as a Data Source in Looker Studio.

2. Create Calculated Field:

• In your report, either at the chart level or the data source level (recommended for reusability), click "Add a field".

  1. Give it a clear Field Name: e.g., Session Conversion Rate.

  2. Enter the Formula: SUM(Conversions) / SUM(Sessions)

  3. Note: Use the exact metric names available from your GA4 data source. They should be Conversions and Sessions. SUM() ensures correct aggregation.

  4. Set the Type: Numeric > Percent.

  5. Click Save.

1. Use the Metric: Now you can add "Session Conversion Rate" to any table or scorecard, alongside dimensions like Session default channel group, Device category, Date, etc.

Benefits: Persistent metric, highly customizable visuals, easy sharing.

Method 2: GA4 Explorations (Calculated Metrics)

You can also calculate this directly within a GA4 Exploration report.

1. Create Exploration: Go to Explore and start a Free form exploration.

2. Add Base Metrics: Ensure Conversions and Sessions are added to the Metrics section in the Variables column.

3. Create Calculated Metric:

• Under Variables > Metrics, click the "+" sign.

  1. Select "Calculated metric".

  2. Give it a Name: e.g., Calculated Session CR.

  3. Enter the Formula: {Conversions} / {Sessions} (Use the metric picker to select them).

  4. Set the Unit of Measurement: Percent.

  5. Click Save.

1. Use the Metric: Drag your new Calculated Session CR into the Metrics section of the Tab Settings column. You can then view it alongside dimensions like Session source / medium.

Limitations:

• Calculated metrics in Explorations are limited (usually 5 per exploration for standard properties).

• They are not reusable across different Explorations; you have to recreate them.

• Explorations are more susceptible to data thresholding, which might hide results if your segments are too small.

Method 3: BigQuery (Advanced)

If you have linked GA4 to BigQuery, you gain ultimate flexibility. The SQL query would look something like this (simplified):

SELECT
  COUNT(DISTINCT CASE WHEN event_name = 'your_conversion_event_name' THEN CONCAT(user_pseudo_id, (SELECT value.int_value FROM UNNEST(event_params) WHERE key = 'ga_session_id')) ELSE NULL END) AS conversion_sessions,
  COUNT(DISTINCT CONCAT(user_pseudo_id, (SELECT value.int_value FROM UNNEST(event_params) WHERE key = 'ga_session_id'))) AS total_sessions,
  SAFE_DIVIDE(
    COUNT(DISTINCT CASE WHEN event_name = 'your_conversion_event_name' THEN CONCAT(user_pseudo_id, (SELECT value.int_value FROM UNNEST(event_params) WHERE key = 'ga_session_id')) ELSE NULL END),
    COUNT(DISTINCT CONCAT(user_pseudo_id, (SELECT value.int_value FROM UNNEST(event_params) WHERE key = 'ga_session_id')))
  ) * 100 AS session_conversion_rate
FROM
  `your_project.your_dataset.events_*` -- Your BigQuery table
WHERE
  _TABLE_SUFFIX BETWEEN 'YYYYMMDD' AND 'YYYYMMDD' -- Your date range

This requires SQL knowledge and a BigQuery setup but offers the most granular control.

Calculating User Conversion Rate in GA4

User Conversion Rate metric provides a different perspective: "What percentage of my unique users performed a conversion action within this time period?"

Definition: (Total Converting Users / Total Users) * 100%

Note: GA4 does have metrics named Converting users and Total users.

Method 1: Looker Studio

Similar to Session CR, Looker Studio is efficient.

1. Connect GA4: Ensure your data source is connected.

2. Create Calculated Field:

• Field Name: e.g., User Conversion Rate.

  1. Formula: SUM(Converting Users) / SUM(Total Users)

  2. Verify: Use the exact Converting Users and Total Users metrics from your GA4 source.

  3. Type: Numeric > Percent.

  4. Save.

1. Use: Apply this metric in charts alongside dimensions like Audience name, First user default channel group, Date, etc.

Method 2: GA4 Explorations

1. Create Exploration: Start a Free form exploration.

2. Add Base Metrics: Add Converting users and Total users to Variables > Metrics.

3. Create Calculated Metric:

• Name: e.g., Calculated User CR.

  1. Formula: {Converting users} / {Total users}.

  2. Unit of Measurement: Percent.

  3. Save.

1. Use: Add to your Exploration's Metrics configuration.

Limitations: Same as with Session CR (limits per exploration, not reusable, potential thresholding).

Method 3: BigQuery

Requires SQL to count distinct users who triggered a conversion event versus the total distinct users in the period.

SELECT
  COUNT(DISTINCT CASE WHEN event_name = 'your_conversion_event_name' THEN user_pseudo_id ELSE NULL END) AS converting_users,
  COUNT(DISTINCT user_pseudo_id) AS total_users,
  SAFE_DIVIDE(
    COUNT(DISTINCT CASE WHEN event_name = 'your_conversion_event_name' THEN user_pseudo_id ELSE NULL END),
    COUNT(DISTINCT user_pseudo_id)
  ) * 100 AS user_conversion_rate
FROM
  `your_project.your_dataset.events_*`
WHERE
  _TABLE_SUFFIX BETWEEN 'YYYYMMDD' AND 'YYYYMMDD'

Specific Use Case: Landing Page Conversion Rate

A common need is to understand how effectively different landing pages initiate sessions that eventually lead to a conversion.

Goal: Calculate the Session Conversion Rate specifically for sessions that started on a particular landing page.

Challenge: This requires combining the Landing Page dimension with our calculated Session Conversion Rate.

Implementation (Looker Studio Preferred):

1. Calculate Session CR: Ensure you have the Session Conversion Rate calculated field created (as per Section 5, Method 1).

2. Create a Table: Add a table chart to your report.

3. Set Dimension: Choose the dimension Landing page + query string. (Note: GA4 often uses Landing page + query string. There might also be just Landing page available).

4. Set Metrics: Add metrics like Sessions and your calculated Session Conversion Rate.

5. Analyze: Sort the table by Session Conversion Rate (descending) or Sessions (descending) to find top performers or pages needing optimization.

6. Filter (Optional): You might want to add a filter to exclude (not set) landing pages for cleaner analysis.

Implementation (GA4 Explorations):

1. Create Exploration: Start a Free form exploration.

2. Add Dimension: Add Landing page + query string to the Dimensions in the Variables column.

3. Calculate Session CR: Create the Calculated Session CR metric (as per Section 5, Method 2).

4. Configure Tab:

• Drag Landing page + query string to Rows.

  1. Drag Sessions, Conversions, and your Calculated Session CR to Metrics.

1. Analyze: View the resulting table.

Caveat: Landing page reports with many low-traffic pages are particularly susceptible to thresholding in GA4 Explorations, which might hide valuable data. Looker Studio often handles this more gracefully.

Specific Use Case: eCommerce & Add-to-Cart Rates

Let's revisit eCommerce, as it has some nuances.

Built-in GA4 eCommerce Rates (Recap):

Remember, if you've implemented standard GA4 eCommerce events (view_item, add_to_cart, begin_checkout, purchase), GA4 does offer useful item-centric rates like Purchase-to-view rate and Cart-to-view rate, plus a session-based eCommerce conversion rate (often labeled Session conversion rate in Monetization reports) focusing specifically on the purchase event. Check your Monetization reports first!

Calculating a Classic eCommerce Conversion Rate:

If the built-in rate isn't sufficient or you want to compare it across other conversion types consistently, you can calculate it:

• Definition: (Total Ecommerce Purchases / Total Sessions) * 100%

• Calculation: Use the methods from Section 5 (Session CR).

• In Looker Studio/Explorations, the formula is SUM(Ecommerce purchases) / SUM(Sessions). (Use the exact metric names provided by the GA4 connector/interface).

  1. Make sure your purchase event is correctly tracked and contributing to the Ecommerce purchases metric.

Calculating Add to Cart Rate (Session Based):

This answers: "What percentage of sessions included an 'add to cart' action?"

• Definition: (Sessions with at least one add_to_cart event / Total Sessions) * 100%

• Challenge: This requires counting unique sessions where the event occurred, which can be tricky outside of BigQuery.

• Implementation (Looker Studio - Advanced Calculated Field): This often requires manipulating data or using specific connector features. A potential formula might look like COUNT_DISTINCT(CASE WHEN Event name = 'add_to_cart' THEN CONCAT(User pseudo ID, Session ID) ELSE NULL END) / COUNT_DISTINCT(CONCAT(User pseudo ID, Session ID)). This depends heavily on the exact fields exposed by the connector and needs careful testing.

• Implementation (GA4 Explorations - Proxy Metric): A true session-based rate is hard here. You can easily calculate an Event-to-Session Ratio:

• Calculated Metric Formula: {Event count with event name = add_to_cart} / {Sessions}.

  1. This tells you the average number of times add_to_cart occurred per session, not the % of sessions it occurred in. It's a proxy for engagement but differs from the classic definition.

• Alternative Definition (Event Frequency): (Total add_to_cart events / Total Sessions) * 100%. This is simpler:

• Looker Studio/Explorations Formula: SUM(Event count where event name = add_to_cart) / SUM(Sessions). (Select the add_to_cart event count metric). This is easy to calculate but measures frequency, not session penetration.

Choose the Add-to-Cart rate definition that makes sense for your analysis and be clear about what you're measuring. For the classic session-based rate, Looker Studio (with potential complexity) or BigQuery are your best bets.

Potential Pitfalls & Considerations

When working with GA4 conversion rates, keep these points in mind:

• Accurate Event Tracking: Garbage in, garbage out. If your session_start events are faulty, or your conversion events (form_submission, purchase, add_to_cart, etc.) aren't firing reliably and accurately, your calculated rates will be meaningless. Double-check your implementation!

• Thresholding: GA4's privacy protection measure. If you slice your data too thinly (e.g., Landing Page by City by Device for a low-traffic site) in Explorations, GA4 might hide rows with small user counts to prevent individual identification. Looker Studio is sometimes less affected, but be aware of "(other)" rows or unexpectedly low totals.

• Data Sampling: While standard GA4 reports are generally unsampled, complex queries in Explorations on properties with very large data volumes can trigger sampling. Look for the sampling indicator (shield icon).

• Data Latency: Conversion data, especially attributed data, can take 24-48 hours to fully process and stabilize in GA4 reports. Avoid making critical decisions based on the last few hours of data.

• Attribution Models: Conversion counts can differ slightly between standard reports (which often use the property's default reporting model, like Data-driven) and Explorations (where you might apply different models). Be consistent in your comparisons.

Ensure Your Conversion Data Is Reliable with Watson GA4 Audit Dashboard

Before diving into complex conversion rate calculations, it's crucial to validate that your tracking fundamentals are solid. After all, the conversion rates we've discussed throughout this article are only as accurate as the data feeding them. The Watson GA4 Audit Dashboard offers a comprehensive solution with 58+ automated checks specifically designed to verify your GA4 implementation, including critical eCommerce event sequences that impact conversion calculations. This free tool examines whether your funnel events like view_item, add_to_cart, begin_checkout, and purchase are properly configured and firing in the expected proportions—precisely the foundation needed for the conversion rate analyses we've outlined above. Try the Watson GA4 Audit Dashboard for free and ensure your conversion metrics are built on reliable data before making critical business decisions.

Conclusion: Embrace the Calculation

Migrating to GA4 often involves a shift in perspective, especially regarding conversion rates. While GA4 provides raw conversion counts relatively easily once set up, deriving the insightful rates like Session Conversion Rate and User Conversion Rate requires an extra step: calculation.

Don't view this as a limitation, but rather as an opportunity for more tailored analysis. By calculating these metrics yourself, you gain a deeper understanding of the underlying data.

For ongoing monitoring and reporting, Looker Studio stands out as the most flexible and robust solution for creating and visualizing these essential calculated conversion rates. While GA4 Explorations offer in-platform calculation, their limitations make them better suited for ad-hoc analysis.

The most critical step? Ensure your event tracking is accurate and comprehensive. Mark your key events as conversions diligently. With a solid data foundation, calculating the rates you need becomes a manageable—and highly valuable—task. Good luck bringing those crucial conversion rates back into your analysis workflow!

If you want to ensure your data is accurate from the start, don’t miss my guide on how to check if Google Analytics is working. And if you’re running campaigns and noticing mismatches in your numbers, get clarity by reading about the discrepancy between Google Ads and GA4.

FAQs

Let's tackle some common direct questions:

• How do I see any conversion rate in GA4?

A: For standard eCommerce (purchase event), check the Monetization > eCommerce purchases report for a built-in Session conversion rate. For any other conversion event (like leads, sign-ups) or a custom eCommerce CR view, you almost always need to calculate Session Conversion Rate or User Conversion Rate yourself using Looker Studio (recommended) or GA4 Explorations (Sections 5 & 6 above).

• How do I calculate landing page conversion rate in GA4?

A: First, calculate the general Session Conversion Rate (Section 5). Then, use the Landing page + query string dimension in a Looker Studio table or a GA4 Exploration, alongside your calculated Session CR metric, to see the rate for each landing page.

• How do I calculate add to cart rate in GA4?

A: Decide which rate: 1) Item-based (add_to_cart / view_item) might be in Monetization reports if using standard eCommerce. 2) Session-based (Sessions with ATC / Total Sessions) is best calculated in Looker Studio with careful field creation or BigQuery. 3) Event-frequency (Total ATC events / Total Sessions) is a simpler proxy calculable in Explorations or Looker Studio (See Section 8).

• What is user conversion rate in GA4?

• A: It's the percentage of unique users who completed at least one conversion action within your selected date range. The formula is (Converting Users / Total Users) * 100%. It's not a default metric for all conversions and needs calculation (Section 6).

• What is session conversion rate in GA4?

• A: It's the percentage of sessions where at least one conversion event occurred. Formula: (Total Conversions / Total Sessions) * 100%. This is the classic rate familiar from UA, but not a default metric for all conversions in GA4. It requires calculation (Section 5).